This Pilot project is to explore the issue of using assisted cooling of the socket to improve socket comfort. Celsia NanoSpreader Vapor Cooler technology is a novel passive planar cooling technology developed for cooling microprocessors that we believe can be applied to the problem of socket cooling. A leading cause of prosthesis abandonment are comfort issues one of which is they are frequently too hot - particularly at Shoulder disarticulation or forequarter level where the socket covers a large portion of the remaining torso. Additionally, the variable intensity sweating inside of the prosthesis socket produces changes in the signals that surface EMG electrodes detect. Active cooling may offer a solution to this problem. The goal of this project is to provide a lightweight, low cost, passive energy method to move the excess heat from the surface of the skin to the outside of the prosthesis. Celsia is a novel planar cooling technology developed for cooling microprocessors that we think can be applied to the problem of socket cooling. This Pilot project is to explore the issue of using assisted cooling of the sockt to improve socket comfort. The Celsia technology is attractive because it is a completely passive device - no external electrical power is necessary to drive the thermal pumping action which is used to disperse waste heat. In the first year we are proposing to fabricate bypass sockets so that intact individuals may wear a socket similar to that worn by person with shoulder disarticulation amputations. These sockets will be are either solid (no NanoSpreader), have simple hole cutouts for air cooling, or have the NanoSpreader built in. Using these large surface area sockets we will work out the kinks associated with the use of the Nanospreader and any issues involved with integrating them into a prosthetic socket. In the second year we will recruit persons with lower-limb amputations and have them test similar sockets fabricated for the lower-limb. We will have the subjects walk on a level treadmill while wearing these sockets and walking at three different speeds while monitoring the temperature inside the socket and measuring O2 consumption. At the end of each subjects session there should be 4 temperature data sets for No socket, solid socket, socket with cutouts, socket with NanoSpreader.